1. Field of the Invention
This invention relates to a camera which pops a light emitting portion of a flash unit up and down.
2. Description of the Related Art
A conventional method of moving a flash unit case up and down, having the light emitting portion of a flash unit integrated in the body of a camera, by a motor as a drive source, is suggested in U.S. Pat. No. 4,545,667. In this method, a flash unit driving cam driven by a motor is rotated in one direction, and a flash unit case is moved up at the maximum lift position of the driving cam and retracted into the body of a camera by the force of a spring at the minimum lift position of the cam. Specifically, there is provided a first spring for moving the flash unit case up and a second spring for storing a stronger force than that of the first spring and moving the flash unit case down. By driving a driving lever, urged by the second spring for the downward movement, by the driving cam and putting the driving lever aside at the maximum lift position of the driving cam, the flash unit case is moved up by the first spring, while the urging force of the second spring to the driving lever overcomes that of the first spring at the minimum lift position of the driving cam so as to move the flash unit case down.
However, in the above prior art, when the flash unit case is being moved downward during the movement of the cam from the maximum lift position to the minimum lift position, the lift of the cam rapidly changes and the flash unit case is moved by only the force of the spring, resulting in big impulsive sounds and bounds. Furthermore, since the balance of the springs is essential, that is, the force of the second spring for the downward movement should be set sufficiently stronger than that of the first spring, it is difficult to stabilize the retention force of the flash unit case while the flash unit case is being moved down. In addition, since the force of the second spring by a full stroke is changed when the flash unit case is moved up, much energy is lost.